"Jesus H. Christ" is an expletive interjection referencing Jesus Christ. It is typically uttered in anger, surprise, or frustration, though sometimes also with humorous intent.
History
The earliest use of the phrase is unknown, but in his autobiography, Mark Twain observed that it was in general use even in his childhood. Twain refers to an episode from 1847, when he was working as a printer's apprentice; Roger Smith tells the tale thus:
recounts a practical joke a friend played on a revival preacher when Twain was an apprentice in a printing shop that Alexander Campbell, a famous evangelist then visiting Hannibal, hired to print a pamphlet of his sermon. While checking the galleys, Twain's fellow apprentice, Wales McCormick, found he had to make room for some dropped words, which he managed by shortening Jesus Christ on the same line to J. C. As soon as Campbell had read the proofs, he swept indignantly into the shop and commanded McCormick, "So long as you live, don't you ever diminish the Savior's name again. Put it all in." The puckish McCormick obeyed, and then some: he set Jesus H. Christ and printed up all the pamphlets.
Smith suggests that "Jesus H. Christ" is a specifically American profanity, and indicates that at least in his experience it is uttered primarily by men. Quinion, a British author, likewise specifies the phrase as belonging to American English.
Stress pattern
Multiple authors emphasize the practice of placing a strong stress on the "H", relating it in various ways to expletive infixation. Thus Quinion writes:
Its long survival must have a lot to do with its cadence, and the way that an especially strong stress can be placed on the H. You might also think of it as an example of emphatic infixing that loosely fits the models of words like abso-bloody-lutely or tribu-bloody-lation.
Similar remarks were made by the linguist Dwight Bolinger, who mentions "Jesus H. Christ" in a discussion of the strategies used by English speakers to add additional stresses to "highly charged words" for purposes of emphasis. Horberry suggests "The strong emphasis on the H somehow improves the rhythm of its host phrase." The Green's Dictionary of Slang says "the H is redundant other than for rhythm".
Etymology
Using the name of Jesus Christ as an oath has been common for many centuries. But the precise origins of the letter H in the expression Jesus H. Christ are obscure. While many explanations have been proposed, the most widely accepted derivation is from the divine monogram of Christian symbolism. The symbol, derived from the first three letters of the Greek name of Jesus, is transliterated iota-eta-sigma, which can look like IHS, ΙΗϹ, JHS or JHC. For how this learned-sounding abbreviation could have served as the basis for vulgar slang, Smith offers the hypothesis that it was noticed by ordinary people when it was worn as a decoration on the vestments of Anglican clergy. The "JHC" variant would particularly invite interpretation of the "H" as part of a name.
Folk etymology
If this is the most likely origin of the "H", there remains the issue of folk etymology; that is, the sense shared by ordinary people of where the H comes from. Here, a possible origin is the name "Harold"; which indeed is mentioned by Smith as the basis of a variant form, "Jesus Harold Christ". The "Harold" may arise from a common misinterpretation of the phrase in the Lord's Prayer, "Our Father who art in heaven hallowed be thy name." This phrase can be mistakenly interpreted as specifying the name of the Deity, rather than the true reading, which is "may thy name be hallowed". The confusion would arise from the phonetic similarity of hallowed to Harold. Ian Ransom reports another folk etymology in a memoir of his childhood. The context is how local adults habitually yelled at children:
I hailed from devoted Jesus H. Christ territory. As a child, "H" was a middle initial meaning "Holy" and included to honor Jesus while his name was being used to scramble young brains into malleable balls of pure fear. Most folks bellowed the simple "Jesus Christ," so children felt privileged to hear that added "H."
Variants
The number of variant forms, usually with "H" replaced by something longer, is vast. "Jesus Harold Christ" is mentioned above. Smith notes Jesus Holy Christ, Jesus Henry Christ, and Jesus H. Particular Christ. Green's Dictionary of Slang gives Jeezus K. Reist, Jesus F. Christ, Jesus H, Jesus H. Mahogany Christ, Jesus Hopping Christ, Jesus Johnnycake Christ, Jesus X. Christ, and Judas H. Christ. For Smith, the very presence of so many spelled-out variants is part of the humor — and blasphemy — inherent in "Jesus H. Christ". He suggests that the H offers "the power of taking the Lord's name in vain by adding something to it that the imagination is invited to complete: What does the H. stand for? — whatever the errant imagination proposes and the imaginer is disposed to enjoy."
